Two ways to read files line by line in nodejs

Two ways to read files line by line in nodejs

1. By way of readline

   const fs = require('fs');
   const readline  = require('readline');
   
   let rl = readline.createInterface({
         
         
     input: fs.createReadStream("./11.txt")
   })
   rl.on('line', line => {
         
         
     console.log(line);
   })
   

2. By way of stream

   Idea: In the form of stream, read one byte at a time, and then judge whether this subsection is a newline character (the newline character in mac is 0xa0)

   If not, save the byte in a temporary array, if so, transcode these arrays into utf8 in the form of Buffer

   The following case is: read a file, then add "" to each line, put it into an array, and then write it into a new file.

   const fs = require("fs");
   
   let readStream = fs.createReadStream("./11.txt");
   let writeStream = fs.createWriteStream("./11_11.txt");
   let buffer = [];
   
   function writeFileWithLine(line, isLastLine) {
   	writeStream.write('\t"');
   	writeStream.write(line);
   	if (isLastLine) {
       writeStream.write('"\n')
   	} else {
   		writeStream.write('",\n');
   	}
   }
   writeStream.write("[\n");
   readStream.on("readable", () => {
   	while ((char = readStream.read(1)) !== null) {
   		if (char[0] === 0x0a) {
   			writeFileWithLine(Buffer.from(buffer).toString(), false);
   			buffer.length = 0;
   		} else {
   			buffer.push(char[0]);
   		}
   	}
   });
   readStream.on("end", () => {
   	writeFileWithLine(Buffer.from(buffer).toString(), true);
   	writeStream.write("]");
   });